The present invention refers to microporous crystalline materials, particularly materials of a zeolitic nature, and specially materials of a zeolitic nature useful in the separation and transformation of organic compounds.
Zeolites are microporous crystalline materials formed by a crystalline network of tetrahedrons TO4 that share all their vertices leading to a three dimensional structure that contains channels and/or cavities of molecular dimensions. They are of a variable composition, and T generally represents atoms with a formal +3 or +4 oxidation status, such as, for example Si, Ge, Ti, Al, B, Ga, . . . If any of the T atoms has an oxidation status of less than +4, the crystalline network formed shows negative charges that are compensated by means of the presence of organic or inorganic cations in the channels and cavities. Organic molecules and H2O can also be lodged in said channels and cavities, for which, in a general manner, the chemical composition of the zeolites can be represented by means of the following empirical formula:
x(M1/nXO2):yYO2:zR:w H2O
wherein M is one or various organic or inorganic cations with +n charge; X is one or various trivalent elements; Y is one or various tetravalent elements, generally Si; and R is one or various organic substances. Although by means of post-synthesis treatments the nature of M, X, Y and R and the values of x, y, z and w can be varied, the chemical composition of a zeolite (as synthesised or after its calcination) possesses a characteristic range for each zeolite and its method of being obtained.
On the other hand, the crystalline structure of each zeolite, with a specific system of channels and cavities, leads to a characteristic X-ray diffraction pattern. Therefore, the zeolites are differentiated among themselves through their range of chemical composition plus their X-ray diffraction pattern. The two characteristics (crystalline structure and chemical composition) also determine the physical and chemical properties of each zeolite and its possible application in different industrial processes.
The present invention refers to a microporous crystalline material of a zeolitic nature, (also identified as xe2x80x9cITQ-15xe2x80x9d), to its method of preparation and its uses in processes for the separation and transformation of organic compounds.
This material is characterised by its X-ray diffraction pattern and by its chemical composition. In its anhydrous and calcinated form, the chemical composition of ITQ-15 can be represented by means of the empirical formula
x(M1/nXO2):yYO2:zGeO2:(1xe2x88x92z)TO2
wherein
x has a value of less than 0.2;
y has a value of less than 0.1;
z has a value of less than 1,
with at least one of x, z and y being greater than zero;
M is H+ or one or various inorganic cations with a +n charge;
X is at least one chemical element with a +3 oxidation status;
Y is one or various chemical elements with a + oxidation status; and
T is at least one chemical element with a +4 oxidation status;
The existence of defects in the crystalline network is possible, however, in terms of the method of synthesis and of its calcination or later treatments, which are shown by the presence of Si-OH groups (silanols). These defects have not been included in the above empirical formula.
The material of the invention is also characterised by its X-ray diffraction pattern as synthesised, obtained by the powder method using a slit of fixed divergence characterised by the following values of interplanar spacings (d) and relative intensities (I/I0) of the most intense reflections.
On the other hand, the material according to the invention is also characterised because, in a calcinated and anhydrous state, it has the following X-ray diffraction pattern.
The positions, widths and relative intensities of some secondary peaks can depend to a certain extent on the chemical composition of the material. In this way, when the network of materials is composed exclusively of silicon and germanium oxide, with a Si/Ge=10 ratio and synthesised using a quaternary ammonium cation as a structure directing agent, the material, as it is synthesised has the ray diffraction pattern shown in table III.
On the other hand, table IV shows the values of interplanar spacings (d) and relative intensities of the most intense reflections of the powder X-ray diffractogram of the same sample of ITQ-15 whose values, after having been calcinated at 540xc2x0 C. to eliminate the organic compounds occluded inside the zeolite, are as follows:
In the previous tables, VW means very weak, W weak, M medium, S strong and VS very strong.
In a first embodiment of the material according to the invention, in the empirical formula identified above, T is Si, in such a way that the resulting empirical formula is:
x(M1/nXO2):yYO2:zGeO2:(1xe2x88x92z)SiO2
wherein x has a value of less than 0.1, preferably less than 0.2, y has a value of less than 0.05 and preferably less than 0.02, z has a value of less than 0.1, M is H+ or one or various inorganic cations with a +n load, X is one or various chemical elements with a +3 oxidation status (preferably Al, Ga, B, Cr) and Y is one or various chemical elements with a +4 oxidation status (preferably Ti, Sn, V).
In a second embodiment of the material according to the invention, in the general empirical formula identified above, T is Si and y is zero, in such a way that the resulting empirical formula is
x(M1/nXO2):zGeO2:(1xe2x88x92z)SiO2
wherein x has a value of less than 0.2, preferably less than 0.1 and more preferably less than 0.02, z has a value of less than 1 and more preferably less than 0.1; M is H+ or one or various inorganic cations with a +n charge and X is one or various chemical elements with a +3 oxidation status (preferably Al, Ga, B, Cr).
In a third embodiment of the material according to the invention, in the general empirical formula identified above, T is Si and y is zero, in such a way that the resulting empirical formula is
yYO2:z GeO2:(1xe2x88x92z)SiO2
wherein y has a value of less than 0.1, preferably less than 0.05 and more preferably less than 0.02, z has a value of less than 1, preferably less than 0.1 and Y is one or various chemical elements with a +4 oxidation status (preferably Ti, Sn or V).
In a fourth embodiment of the material according to the invention, in the general empirical formula identified above, T is Si and x is zero, in such a way that the resulting empirical formula is
x(HXO2):zGeO2:(1xe2x88x92z)SiO2
in which X is a trivalent element (preferably Al, Ga, B, Cr), x has a value of less than 0.2, preferably less than 0.1, and more preferably less than 0.02, z has a value of less than 1, and more preferably less than 0.1.
In a fifth embodiment of the material according to the invention, in the general empirical formula identified above, T is Si and x is zero, in such a way that the resulting empirical formula is
zGeO2:(1xe2x88x92z)SiO2
wherein z has a value below 1 and preferably below 0.1.
In a sixth embodiment of the material according to the invention, in the general empirical formula identified above, z and y are zero, so that the resulting empirical formula is
X(M1/nXO2):TO2
wherein x has a value of less than 0.2; M is H+ or one or various inorganic cations with a +n charge; X is one or various chemical elements with a +3 oxidation (preferably Al, Ga, B, Cr) and T is one or various chemical elements with a +4 oxidation state (preferably Si, Ti, Sn, V).
This invention also refers to the method of preparation of ITQ-15. This includes thermal treatment at a temperature between 80 and 200xc2x0 C., preferably between 130 and 200xc2x0 C., of a reaction mixture that contains a source of SiO2 (such as, for example, tetraethylorthosilicate, colloidal silica, amorphous silica), a source of GeO2, an organic cation in the form of hydroxide, preferably di-hydroxide of 1,3,3-trimethyltricycle-6-azonium[3.2.1.46,6] dodecane and water. Alternately, it is possible to use the organic cation in the form of salt (for example, a halide, preferably chloride or bromide) and adding an alkali or alkali-earth source, preferably in the form of hydroxide. Cation I has two asymmetrical carbons and can be used as any of its two enantiomers, as a mixture of both or as a racemic mixture.
Optionally, it is possible to add a source of another or other tetravalent Y and/or trivalent X element(s), preferably Ti, V, Sn or Al, B, Ga, Fe. The adding of this or these element(s) can be performed before the heating of the reaction mixture or in an intermediate time during this heating. On occasions, it may also be convenient to include ITQ-15 crystals at some time during the preparation (between 0.01 and 15% by weight with regard to the group of inorganic oxides, preferably between 0.05 and 5% by weight) as promoters of the crystallisation (sowing). The composition of the reaction mixture responds to the general empirical formula
rROH:aM1/nOH:xX2O3:yYO2:zGeO2:(1xe2x88x92z)SiO2:wH2O
wherein M is H+ or one or various inorganic cations with a +n charge; X is one or various trivalent elements, preferably Al, B, Ga, Fe; Y is one or various tetravalent elements, preferably Ti, Sn, V; R is an organic cation, preferably 1,3,3-trimethyltricycle-6-azonium[3.2.1.46,6] dodecane; and the values of r, a, x, y, z, and w are in the following ranges:
r=ROH/SiO2=0.01-1.0, preferably between 0.1-1.0.
a=M1/nOH/SiO2=0-1.0, preferably 0-0.2.
x=X2O3/SiO2=0-0.1, preferably between 0-0.05 and more preferably between 0-0.01.
y=YO2/SiO2=0-0.1, preferably between 0-0.05 and more preferably between 0-0.02.
z=GeO2/(SiO2+GeO2) below 1, preferably less than 0.1.
w=H2O/SiO2=0-100, preferably 1-50, more preferably between 1-15.
The thermal treatment of the reaction mixture can be executed statically or under stirring the mixture. Once the crystallisation has finished the solid product is separated and dried. Later calcination at temperatures between 400 and 650xc2x0 C., preferably between 450 and 600xc2x0 C., causes the decomposition of the organic remains occluded in the zeolite and the exit thereof, leaving the zeolitic channels free.
Once calcinated, the material therefore responds to the general formula
x(M1/nXO2):yYO2:zGeO2:(1xe2x88x92z)SiO2
wherein x has a value below 0.2, preferably below 0.1, and more preferably below 0.02, with the possibility of being equal to zero; y has a value below 0.1, preferably below 0.05 and more preferably below 0.02, with the possibility of being equal to zero; z has a value below 1, preferably below 0.1; M is H+ or one or various inorganic cations with a +n charge; X is one or various chemical elements with a +3 oxidation status (preferably Al, Ga, B, Cr) and Y is one or various chemical elements with a +4 oxidation status (Ti, Sn, V).
The following applications are claimed for synthesised ITQ-15 zeolite in this description:
As an additive of hydrocarbon catalytic cracking catalysts, and in general, of organic compounds.
As a component of hydro-cracking and soft hydro-cracking catalysts.
As a component or additive of light paraffin isomerization catalysts.
As a component of de-paraffining and iso-paraffining catalysts.
As a catalyst of alkylation of isoparaffins with olefins and alkylation of aromatics and substituted aromatics with olefins and alcohols, and more specifically as a catalyst for the alkylation of benzene with propylene.
As a catalyst in acylation reactions of substituted aromatic compounds using acids, acid chlorides or organic acid anhydrides as acylating agents.
As catalysts in Meerwein-Pondorf-Verley and Oppenauer reactions.
In the case of the ITQ-15 containing Ti, it can be used as catalyst for the epoxidation of olefins, oxidation of alkanes, oxidation of alcohols and oxidation of thioethers to sulphoxides and sulphones using organic or inorganic hydroperoxide, as for example H2O2, tertbutylhydroperoxide, cumene hydroperoxide, as oxidating agents.
In the case of containing Sn, the ITQ-15 can be used as oxidating catalysts in Bayer-Villiger reactions using H2O2 as an oxidating agent. Finally, its use is described in ammoximation of cetones, and more specifically of cyclohexanone oxyme with NH3 and H2O.